Plasmon Ag decorated 3D urchinlike N-TiO2-x photocatalysts are successfully synthesized by a facile hydrothermal treatment (180 degrees C) and combined with a photo-deposition approach, followed by a reduction treatment. The results show that the resultant Ag/N-TiO2-x sample possesses a three-dimensional (3D) urchinlike nanostructure with high crystallinity of anatase. Meanwhile, it exhibits the narrow optical band gap (Eg similar to 2.61 eV) and the excellent visible-light-driven photocatalytic performance. Moreover, the hydrogen generation rate and photocatalytic degradation rate of phenol are up to 186.2 mu mol h(-1) g(-1) and 97.7% under visible light irradiation, which are about 4.2 and 5.4 folds greater than that of N-TiO2. The mechanism of photocatalytic process is also proposed, and the enhanced photocatalytic property is mainly due to the synergistic reaction of the Ti3+ and N codoping, which narrows the band gap and favors the utilization of visible light, and the plasmon effect of Ag nanoparticles and unique 3D urchinlike architecture, which are propitious to the separation and transmission of photogenerated carriers. (C) 2018 Elsevier Inc. All rights reserved.